A method for smelting ingot material 08Ni3DR

Abstract

The application discloses a smelting method of ingot material 08Ni3DR, which comprises production preparation, an electric furnace, an LF refining furnace, a VD vacuum furnace and a casting process; the electric furnace process is loaded with ferro-nickel with a nickel content of 8-40%, no material is added during tapping, and the tapping Ni is greater than or equal to 2.50%; the LF refining furnace process is first dephosphorized outside the furnace, then vacuum decarburization and deoxidation are carried out, then the nickel content is adjusted to meet the component requirement by using ferro-nickel with a nickel content of 8-40%, and slagging is carried out after refining; the VD vacuum furnace process is not subjected to calcium treatment before vacuum, the vacuum degree is less than or equal to 66 Pa and is kept for 18-23 min, rice husk is added to cover the liquid surface after breaking the vacuum, and non-oxidized soft blowing is carried out for 6-15 min. The smelting method realizes complete replacement of nickel plate by ferro-nickel in the smelting process of 08Ni3DR, and the alloy cost is greatly reduced; the low P component requirement of 08Ni3DR is realized, the smelting P is less than or equal to 0.008%, and the flaw detection qualified rate is greater than or equal to 97.5%.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of steel metallurgy, and particularly relates to a smelting method of ingot material 08Ni3DR. BACKGROUND

[0002] 08Ni3DR is a kind of steel plate for low-temperature pressure vessels, commonly known as (3.5Ni) steel, which has good impact toughness and mechanical properties in a low-temperature working environment, and is usually used in a low-temperature environment of-70 to-101 DEG C (the quenched and tempered state can reach-107 DEG C). The 08Ni3DR has the characteristics of low carbon, low phosphorus and high nickel in component design. In recent years, the price of nickel has been rising continuously, and the smelting cost of nickel-containing steel is under great pressure. The low-carbon and low-phosphorus components are not easy to control, which seriously restricts contract acceptance. Therefore, it is urgent to develop a smelting method with low cost, controllable component and controllable flaw detection. SUMMARY

[0003] The technical problem to be solved by the application is to provide a smelting method of ingot material 08Ni3DR, which can completely replace high-price nickel plate with low-price nickel iron in the smelting process, the component of the molten steel is controllable, the smelting P is less than or equal to 0.008%, the internal cleanliness of the molten steel is ensured, and the internal quality of the steel plate meets the flaw detection standard of the acceptance level Level I of NB / T47013.3-2015.

[0004] To solve the above technical problems, the technical scheme adopted by the application is:

[0005] A smelting method of ingot material 08Ni3DR, comprising a production preparation process, an electric furnace process, an LF refining furnace process, a VD vacuum furnace process and a casting process.

[0006] The production preparation process of the application selects a normal turnover ladle and a flat ladle lining, so as to facilitate off-furnace dephosphorization.

[0007] The electric furnace process of the application loads 25-40 tons of nickel iron with a nickel content of 8-40% according to the planned tapping amount, does not add materials during tapping, that is, does not alloy, and ensures that the tapping Ni is greater than or equal to 2.5%.

[0008] The LF refining furnace process of the application first dephosphorizes off the furnace to P less than or equal to 0.003% after the ladle is seated in the LF, then de-carbonizes and de-oxygenates to reduce the carbon and oxygen content of the molten steel, smelts in the LF after de-carbonization and de-oxygenation, continues to add nickel iron with a nickel content of 8-40% to adjust the nickel content of the molten steel during the smelting process, and performs slagging operation after refining.

[0009] The off-furnace dephosphorization of the application specifically operates as follows: after the ladle is seated in the LF, 700-1000 kg of lime and 300-500 kg of fluorite are added, the temperature is raised to 1540-1570 DEG C by sending electricity, argon stirring is performed for 3-5 min, and then argon blowing and slagging operations are performed.

[0010] The VD vacuum furnace process does not feed calcium wire before vacuum, maintains a vacuum degree of ≤66 Pa for 18-23 min, and adds rice husks to cover the liquid steel surface after breaking the vacuum, and the non-oxidizing soft blowing time is 6-15 min.

[0011] The pouring process covers the ladle and pours the steel, and the pouring superheat degree is controlled to be 43-49℃.

[0012] The steel plate NB1 produced by the method has a flaw detection qualified rate of ≥97.5%.

[0013] The beneficial effects produced by the above technical solution are as follows:

[0014] The present application selects a good normal turnover ladle through the production preparation process, adds low-price nickel iron in the electric furnace process, uses low-price nickel iron after dephosphorization, decarburization and deoxidization in the LF refining furnace, maintains for 18-23 min in the VD vacuum furnace process, covers and pours the steel in the pouring process, and the superheat degree is 43-49℃. The present application not only realizes the reduction of smelting cost, but also realizes the controllability of the composition and internal quality of the liquid steel.

[0015] The ingot produced by the smelting method realizes the complete replacement of nickel plate by nickel iron, greatly reduces the alloy cost, realizes the controllability of the composition of the liquid steel and the melting P≤0.008%, and the flaw detection qualified rate of the steel plate NB1 after rolling is ≥97.5%.

[0016] The present application not only develops a smelting method of ingot material 08Ni3DR, but also provides a certain reference value for the smelting of other types of low-carbon low-phosphorus high-nickel steel. Embodiment

[0017] The present application will be further described in detail below in combination with specific examples. Example 1

[0018] A smelting method of ingot material 08Ni3DR, including a production preparation process, an electric furnace process, an LF refining furnace process, a VD vacuum furnace process, and a pouring process, is as follows:

[0019] (1) The production preparation process: the ladle is offline for 3.5 h, and the ladle edge is flattened.

[0020] (2) The electric furnace process: 29 t of nickel iron with a nickel content of 9.7% is loaded, the tapping amount is 86.9 t, the tapping sample Ni is 2.69%, and the tapping is not alloyed.

[0021] (3) LF refining furnace process: after sitting package, off-line dephosphorization: add lime 700 kg, fluorite 300 kg, heat to 1540 ℃, take sample after large argon stirring for 3 min, then perform argon blowing and slagging operation, sample return liquid steel P: 0.002%; after dephosphorization, perform vacuum decarburization and deoxidation, after decarburization and deoxidation, continue to add nickel content 9.7% ferro-nickel 4.6 t, after refining, the nickel content of the liquid steel meets the requirements, and the slag is removed.

[0022] (4) VD vacuum furnace process, no calcium treatment before vacuum, vacuum degree 66 Pa, keep for 18 min, after breaking, add rice husk to cover the liquid steel surface, no oxidation, soft blowing at normal pressure for 6 min.

[0023] (5) Casting process, cover the ladle to pour the steel, liquidus 1518 ℃, pouring temperature 1563 ℃, superheat 45 ℃.

[0024] The smelting method produces 08Ni3DR (ingot type 28.4*3), no nickel plate is used in the smelting process, the smelting composition is in accordance with the standard, P: 0.004%, and the NB1 level flaw detection of the three ingots after rolling is qualified. Example 2

[0025] A smelting method of ingot material 08Ni3DR, comprising a production preparation process, an electric furnace process, an LF refining furnace process, a VD vacuum furnace process and a casting process, and specifically as follows:

[0026] (1) Production preparation process: the ladle is leveled along the line for 4 h after being taken offline;

[0027] (2) Electric furnace process: 35 t of ferro-nickel with a nickel content of 23.8% is loaded, the tapping amount is 101.5 t, the tapping sample Ni: 2.93%, and the tapping is not alloyed.

[0028] (3) LF refining furnace process: after sitting package, off-line dephosphorization: add lime 700 kg, fluorite 300 kg, heat to 1540 ℃, take sample after large argon stirring for 3 min, then perform argon blowing and slagging operation, sample return liquid steel P: 0.002%; after dephosphorization, perform vacuum decarburization and deoxidation, after decarburization and deoxidation, continue to add nickel content 9.7% ferro-nickel 4.6 t, after refining, the nickel content of the liquid steel meets the requirements, and the slag is removed.

[0029] (4) VD vacuum furnace process, no calcium treatment before vacuum, vacuum degree 66 Pa, keep for 18 min, after breaking, add rice husk to cover the liquid steel surface, no oxidation, soft blowing at normal pressure for 6 min.

[0030] (5) Casting process, cover the ladle to pour the steel, liquidus 1518 ℃, pouring temperature 1563 ℃, superheat 45 ℃.

[0031] The smelting method produces 08Ni3DR (ingot type 51x2), and no nickel plate is used in the smelting process, the smelting composition is standard, and P: 0.004%, and the NB1 level flaw detection of two steel ingots after rolling is qualified. Example 3

[0032] A smelting method of ingot material 08Ni3DR, comprising a production preparation process, an electric furnace process, an LF refining furnace process, a VD vacuum furnace process, and a casting process; specifically as follows:

[0033] (1) Production preparation process: the ladle is offline for 1h, and the ladle is leveled;

[0034] (2) Electric furnace process: 40t of nickel iron with a nickel content of 39.7% is loaded, the tapping amount is 102.1t, the tapping sample Ni is 3.00%, and the tapping is not alloyed.

[0035] (3) LF refining furnace process: after the ladle is seated, the off-furnace dephosphorization is carried out: 850kg of lime and 400kg of fluorite are added, the temperature is raised to 1555℃, the sample is taken after 4min of large argon stirring, then the argon blowing and slagging operation is carried out, the sample returns the liquid steel P: 0.002%; after dephosphorization, vacuum decarburization and deoxidation are carried out, the LF furnace is seated after decarburization and deoxidation, 0.75t of nickel iron with a nickel content of 39.7% is continuously added, the nickel meets the requirements after refining, and the slag is removed.

[0036] (4) VD vacuum furnace process, no calcium treatment before vacuum, the vacuum degree is 64Pa, and the liquid steel surface is covered with rice husk after 21min of keeping, and there is no oxidation in normal pressure soft blowing for 11min.

[0037] (5) Casting process, the ladle cover is used to pour the steel, the liquidus is 1518℃, the pouring temperature is 1564℃, and the superheat degree is 46℃.

[0038] The smelting method produces 08Ni3DR (ingot type 33.52x3), and no nickel plate is used in the smelting process, the smelting composition is standard, and P: 0.004%, and the NB1 level flaw detection of three steel ingots after rolling is qualified. Example 4

[0039] A smelting method of ingot material 08Ni3DR, comprising a production preparation process, an electric furnace process, an LF refining furnace process, a VD vacuum furnace process, and a casting process; specifically as follows:

[0040] (1) Production preparation process: the ladle is offline for 4h, and the ladle is leveled;

[0041] (2) Electric furnace process: 36t of nickel iron with a nickel content of 8.1% is loaded, the tapping amount is 85.2t, the tapping sample Ni is 2.68%, and the tapping is not alloyed.

[0042] (3) LF refining furnace process: after sitting package, add 700 kg of lime and 300 kg of fluorite outside the furnace for dephosphorization, heat to 1560℃, take sample after argon stirring for 5 min, then perform argon blowing and slagging operation, the sample returns the steel liquid P: 0.003%; after dephosphorization, perform vacuum decarburization and deoxidation, sit in the LF furnace after decarburization and deoxidation, continue to add 5.7 t of nickel iron with a nickel content of 8.1%, the nickel meets the requirements after refining, and the slag is removed.

[0043] (4) VD vacuum furnace process, no calcium treatment before vacuum, keep 20 min under a vacuum degree of 66 Pa, add rice husk to cover the steel liquid surface after breaking, and perform soft blowing under normal pressure for 10 min without oxidation.

[0044] (5) Casting process, cover the ladle to pour the steel, the liquidus is 1516℃, the pouring temperature is 1562℃, and the superheat degree is 46℃.

[0045] The smelting method produces 08Ni3DR (ingot type 28.4x3), no nickel plate is used in the smelting process, the smelting composition is standard, P: 0.005%, and the NB1 level flaw detection of the three ingots after rolling is qualified. Example 5

[0046] A smelting method of ingot material 08Ni3DR, including a production preparation process, an electric furnace process, an LF refining furnace process, a VD vacuum furnace process, and a casting process, and specifically as follows:

[0047] (1) Production preparation process: the ladle is offline for 2.5 h, and the ladle is leveled along;

[0048] (2) Electric furnace process: 33 t of nickel iron with a nickel content of 27.6% is loaded, the tapping amount is 103.5 t, the tapping sample Ni is 2.67%, and the tapping is not alloyed.

[0049] (3) LF refining furnace process: after sitting package, add 700 kg of lime and 300 kg of fluorite outside the furnace for dephosphorization, heat to 1570℃, take sample after argon stirring for 3 min, then perform argon blowing and slagging operation, the sample returns the steel liquid P: 0.003%; after dephosphorization, perform vacuum decarburization and deoxidation, sit in the LF furnace after decarburization and deoxidation, continue to add 2.1 t of nickel iron with a nickel content of 27.6%, the nickel meets the requirements after refining, and the slag is removed.

[0050] (4) VD vacuum furnace process, no calcium treatment before vacuum, keep 20 min under a vacuum degree of 65 Pa, add rice husk to cover the steel liquid surface after breaking, and perform soft blowing under normal pressure for 12 min without oxidation.

[0051] (5) Casting process, cover the ladle to pour the steel, the liquidus is 1518℃, the pouring temperature is 1563℃, and the superheat degree is 45℃.

[0052] The smelting method produces 08Ni3DR (ingot type 26.1*4), no nickel plate is used in the smelting process, the smelting composition is standard and P: 0.006%, and after rolling of the four ingots, the NB1 level flaw detection is qualified. Example 6

[0053] A smelting method of ingot material 08Ni3DR, comprising a production preparation process, an electric furnace process, an LF refining furnace process, a VD vacuum furnace process and a casting process, and specifically as follows:

[0054] (1) The production preparation process: the ladle is offline for 3.5 hours, and the ladle is leveled.

[0055] (2) The electric furnace process: 36 tons of nickel iron with a nickel content of 15.4% are loaded, the tapping amount is 93.5 tons, the tapping sample Ni is 2.99%, and the tapping is not alloyed.

[0056] (3) The LF refining furnace process: after the ladle is seated, the off-furnace dephosphorization is carried out: 800 kg of lime and 400 kg of fluorite are added, the temperature is raised to 1540 DEG C, the sample is taken after argon stirring for 4 min, then the argon blowing and slagging operation is carried out, the sample returns the liquid steel P: 0.002%; after dephosphorization, vacuum decarburization and deoxidation are carried out, the LF furnace is seated after decarburization and deoxidation, 1.6 tons of nickel iron with a nickel content of 15.4% is continuously added, the nickel meets the requirements after refining, and the slag is removed.

[0057] (4) The VD vacuum furnace process, no calcium treatment before vacuum, the vacuum degree is 66 Pa, and the liquid steel surface is covered with rice husk after 20 min of keeping, and there is no oxidation after 10 min of soft blowing at normal pressure.

[0058] (5) The casting process, the ladle is covered and the steel is poured, the liquidus is 1518 DEG C, the pouring temperature is 1562 DEG C, and the superheat is 44 DEG C.

[0059] The smelting method produces 08Ni3DR (ingot type 31.24*3), no nickel plate is used in the smelting process, the smelting composition is standard and P: 0.005%, and after rolling of the three ingots, the NB1 level flaw detection is qualified. Example 7

[0060] A smelting method of ingot material 08Ni3DR, comprising a production preparation process, an electric furnace process, an LF refining furnace process, a VD vacuum furnace process and a casting process, and specifically as follows:

[0061] (1) The production preparation process: the ladle is offline for 1.5 hours, and the ladle is leveled.

[0062] (2) The electric furnace process: 32 tons of nickel iron with a nickel content of 33.2% are loaded, the tapping amount is 105.6 tons, the tapping sample Ni is 2.74%, and the tapping is not alloyed.

[0063] (3) LF refining furnace process: after ladle, dephosphorization outside the furnace: add lime 700 kg, fluorite 450 kg, heat to 1550 DEG C, take sample after argon stirring for 5 min, then carry out argon blowing and slagging operation, sample return liquid steel P: 0.003%; after dephosphorization, carry out vacuum decarburization and deoxidation, after decarburization and deoxidation, sit LF furnace, continue to add nickel iron with nickel content 33.2% 1.75 t, after refining, nickel meets the requirements, and slagging.

[0064] (4) VD vacuum furnace process, no calcium treatment before vacuum, keep 63 Pa under vacuum for 21 min, after breaking, add rice husk to cover liquid surface, no oxidation normal pressure soft blowing for 10 min.

[0065] (5) casting process, cover ladle to pour steel, liquidus 1517 DEG C, pouring temperature 1563 DEG C, superheat 46 DEG C.

[0066] The smelting method produces 08Ni3DR (ingot type 26.1*4), no nickel plate is used in the smelting process, the smelting composition is in line with the standard, P: 0.005%, and the 4 ingots are qualified after NB1 grade flaw detection.

[0067] The above examples are only used to illustrate but not to limit the technical solutions of the present application, although the present application is described in detail with reference to the above examples, those skilled in the art should understand that the present application can still be modified or replaced equivalently without departing from the spirit and scope of the present application, any modification or partial replacement should be covered in the scope of the claims of the present application.

Claims

1. A method of smelting ingot material 08Ni3DR, characterized by, The smelting method comprises a production preparation process, an electric furnace process, an LF refining furnace process, a VD vacuum furnace process and a casting process; In the electric furnace process, 25-40 tons of ferronickel with a nickel content of 8-40% is loaded according to the planned tapping amount, and no material is added during tapping, and the tapping Ni is greater than or equal to 2.5%; In the LF refining furnace process, after the ladle is seated, the ladle is first dephosphorized outside the furnace to P less than or equal to 0.003%, and then the ladle is seated in the VD furnace for vacuum decarburization and deoxidation; after the decarburization and deoxidation, the ladle is seated in the LF furnace for smelting, and during the smelting process, ferronickel with a nickel content of 8-40% is continuously added to adjust the nickel content of the molten steel, and after the refining, the slag is removed; In the VD vacuum furnace process, no calcium treatment is performed before vacuum, the vacuum degree is less than or equal to 66 Pa, and the vacuum is maintained for 18-23 min, after the vacuum is broken, rice husk is added to cover the molten steel surface, and the molten steel is soft blown for 6-15 min without oxidation; In the casting process, the ladle is covered when the molten steel is poured, and the pouring superheat is controlled to be 43-49 DEG C; The specific operation of the dephosphorization outside the furnace is as follows: after the ladle is seated, 700-1000 kg of lime and 300-500 kg of fluorite are added, the temperature is raised to 1540-1570 DEG C by power transmission, argon stirring is performed for 3-5 min, and then argon blowing and slag removal are performed; The 08Ni3DR produced by the smelting method is completely replaced by ferronickel instead of nickel plate during the smelting process, the smelting P is less than or equal to 0.008%, after different ingot types are rolled, the steel plate NB / T47013.3-2015 acceptance level Level I flaw detection qualified rate is greater than or equal to 97.5%.

2. A method of smelting ingot material 08Ni3DR according to claim 1, characterized in that, In the production preparation process, a normal turnover ladle is selected, and the ladle is flattened.

3. A method of smelting ingot material 08Ni3DR according to claim 2, characterized in that, The normal turnover ladle refers to that the ladle offline time is less than or equal to 4 h.